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UNITED STATES PATENT OFFICE.

JOSEPH D. GREENE AND EDWARD IVERS, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNORS TO JOSEPH D. GREENE.

AIR-HEATING FURNACE.

vSpecification of Letters Patent No. 16,348, dated January 6, 1857.

To all whom it may concern.'

Be it known that we, JOSEPH D. GREENE and EDWARD IvERs, of the city and county` of Philadelphia and State of Pennsylvania, have invented a new and Improved Air- Heating Apparatus; and we do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, making a part of this specification, Figure l being a side elevation thereof, and Fig. 2 a Vertical section in a line passing from front to rear through the center of said apparatus.

Similar letters indicate like parts in both figures.

The furnace B, of our heating apparatus, is placed over a central opening in the top of the chamber A, whose diameter is nearly double that of said furnace; and the upper end of the furnace cylinder is connected to the sides of a vertical radiating cylinder F, by means of a horizontal annular plate g. The upper end of the cylinder F, terminates in the enlargement E, whose diameter corresponds with that of the chamber A, which forms the base of the apparatus. A series of vertical conical tubes C, C, arranged immediately around the outside of the cylinder F, serve to connect the chamber within said cylinder with the base-chamber A, as represented in the drawings; the smallest ends of said tubes passing throughthe annular offset plate which forms the under side of the enlargementE, at the head of the cylinder F; and the largest ends of said tubes passing through the annular plate which `forms the top of the outer portion of the base-chamber A. The said conical tubes o, c, conduct the gaseous products of combustion from the upper portion of the chamber within the cylinder F, down into the base-chamber A, from which chamber the said gaseous products pass off through the flue D.

The series of air-heating conical tubes I, I, are arranged around the inner periphery of the cylinder F; the smallest ends of said tubes passing through the annular plate g, which forms the bottom of the portion of said cylinder which projects beyond the furnace B, and the largest ends of said tubes passing through the top of said cylinder. It will therefore be perceived that the gaseous products of combustion will pass into the smallest ends of the tubes o, o, and will be discharged through their largest ends into the base-chamber A; and'that the cold air will enter the smallest ends of the series of air heating tubes, and the heated air be discharged therefrom through the largest ends of said tubes. This arrangement of the said conical smoke-conducting tubes, we find greatly increases the draft of the furnace, for the reason that the gaseous products of combustion being necessarily drawn through said tubes unnaturally-since the natural movement of said gases is upward-are less impeded than they are during a downward passage through cylindrical tubes, or through the same conical tubes arranged in a reverse position.

To enable the air to pass through the air tubes with a rapidity corresponding with the increased energy of combustion in the furnace chamber, caused by our improved arrangement of the smoke conducting tubes, we have made the series of air tubes I, I, of the aforesaid conical shape and arranged them with their smallest ends downward. And when thus arranged, we find that a much larger quantity of air passes through them than through the same tubes arranged in a reverse position, or through a series of cylindrical tubes whose diameter corresponds with the diameter of the central portion of said series of air conducting conical tubes. Consequently, with an apparatus of a given size7 we are enabled to heat a much larger quantity of air than can be heated in any other apparatus; and the air heated by our apparatus, is less liable to be decomposed than it is during its passage through tubes where its free passage is obst-ructed. The cause of the freer and more rapid passage of the air through the said series of inverted conical tubes, will be readily apparent. The air as its volume increases from the effects of heat, is constantly passing into a wider space and will not therefore be crowded or retarded in its natural upward movement. The air will also be heated by means of radiation from the sur faces of the tubes rather than from being forced into close contact with said surfaces. The respective cylinders and tubes of our air heating apparatus may be made of an angular shape if deemed preferable by the manufacturer.

Having thus fully described our improved air-heating apparatus, we would observe that we are aware that a single inverted hollow cone has been used in an auxiliary smoke-receiving drum standing by the side of a furnace cylinder and upon the same ash pit, for the purpose of conducting cold air into the top of said drum, to mingle with the smoke therein and find its way in part, through the bottom of said drum and the ash pit to the furnace chamber, and the remainder pass ofij with the smoke and gaseous products of combustion, as represented in Wm. Ennis patent of March 29th, 1858, and shown by Fig. 3 of the accompanying drawings; and therefore we do not claim to be the first to use a hollow cone in a hot air furnace; but

What We do claim as our invention and desire to secure by Letters Patent, is-

The peculiar arrangement of the double series of smoke-conducting and air-heating tubes with the other parts of our air-heating apparatus; Viz: the series of smoke conducting tubes being arranged around the exterior surface of the furnace chamber with their induction smallest ends uppermost, and the series of air-heating tubes being arranged around the interior surface of the furnace chamber with their induction smallest ends opening downward, and both ends open to the atmosphere, all substantially as herein set forth.

JOS. D. GREENE. EDWARD IVERS. In presence of- ANDREW J. BOSWELL,

BEN MOXEY. 

